Proposed work for the forthcoming year includes: 1) investigation of intramolecular systems which feature nucleophilic attack by carboxylate or amine nitrogen on the phosphorus of phosphate diesters and pyrophosphonates; 2) the attendant effects of metal ions on the systems under 1); 3) purification and establishment of the criteria for homogeneous "neutral" fructose diphosphatase; and 4) experiments designed to demonstrate the possible importance of a ketophosphate in the fructose diphosphatase mechanism of action.